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Acute lymphoblastic leukemia, also known as acute lymphocytic leukemia or acute lymphoid leukemia (ALL), is an acute form of leukemia, or cancer of the white blood cells, characterized by the overproduction and accumulation of cancerous, immature white blood cells, known as lymphoblasts.〔 In persons with ALL, lymphoblasts are overproduced in the bone marrow and continuously multiply, causing damage and death by inhibiting the production of normal cells (such as red and white blood cells and platelets) in the bone marrow and by spreading (infiltrating) to other organs. ALL is most common in childhood, with a peak incidence at 2–5 years of age and another peak in old age.〔 The symptoms of ALL are indicative of a reduced production of functional blood cells, because leukemia wastes the resources of the bone marrow that are normally used to produce new, functioning blood cells.〔 These symptoms can include fever, increased risk of infection (especially bacterial infections like pneumonia, due to neutropenia; symptoms of such an infection include shortness of breath, chest pain, cough, vomiting, changes in bowel or bladder habits), increased tendency to bleed (due to thrombocytopenia), and signs indicative of anemia, including pallor, tachycardia (high heart rate), fatigue, and headache.〔 About 6,000 cases are reported in the United States every year.〔 Internationally, ALL is more common in Caucasians than in Africa; it is more common in Hispanics and in Latin America.〔〔 Cure is a realistic goal and is achieved in more than 80% of affected children, although only 20-40% of adults are cured.〔 "Acute" refers to the relatively short time course of the disease, distinguishing it from chronic lymphocytic leukemia, which has a potential time course of many years. ALL was one of the first cancers for which an effective chemotherapeutic treatment was developed. Antifolates like aminopterin and methotrexate were developed in the late 1940s by Sidney Farber and Yellapragada Subbarow. At that time, a doctor did not need a patient's or parent's consent to try an experimental treatment as the Nuremberg code had not yet been signed. Desperate to save his patients, Farber initially tried folic acid supplementation as a treatment for ALL. This had disastrous consequences and he likely accelerated the children's deaths.〔 == Signs and symptoms == Initial symptoms are not specific to ALL, but worsen to the point that medical help is sought. They result from the lack of normal and healthy blood cells because they are crowded out by malignant and immature leukocytes (white blood cells). Therefore, people with ALL experience symptoms from malfunctioning of their erythrocytes (red blood cells), leukocytes, and platelets. Laboratory tests that might show abnormalities include blood count tests, renal function tests, electrolyte tests, and liver enzyme tests.〔 The signs and symptoms of ALL are variable but follow from bone marrow replacement and/or organ infiltration.〔 * Generalized weakness and fatigue * Anemia * Dizziness * Frequent or unexplained fever and infection * Weight loss and/or loss of appetite * Excessive and unexplained bruising * Bone pain, joint pain (caused by the spread of "blast" cells to the surface of the bone or into the joint from the marrow cavity) * Breathlessness * Enlarged lymph nodes, liver and/or spleen * Pitting edema (swelling) in the lower limbs and/or abdomen * Petechiae, which are tiny red spots or lines in the skin due to low platelet levels 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「acute lymphoblastic leukemia」の詳細全文を読む スポンサード リンク
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